Re: Best way to distribute the weight of a heavy guitar?
None of my Pauls weigh over 9.2 lbs. I use wide soft leather straps from either Franklin or padded Levy's Leathers straps. Three inch wide is optimum, but some of mine are 2.5". I must admit that a G&L Legacy is my Number One, and I'm typically only using a 2HB Paul or 335 for about fifteen songs during a four-hour gig.
I had an auto accident at age 30 and hurt my upper back. I still have some problems with it if I'm not careful. Probably have some arthritic changes. I absolutely would NEVER use the neck strap Maniac posted--that would probably put me in the hospital.
Years ago, Fender used to offer a hip strap. A wide belt designed for bassists, it fit around your waist and put the weight of the instrument on your hips. A women I used to know used one for her P-Bass and loved it. Saved her back. Might want to see if there is a blueprint for one out there on the web.
But the absolute BEST thing you can do is to get yourself into good physical condition and strengthen your upper back, shoulders and neck AND also your lower back. I'm 66 and have the body of a 99 y.o. couch potato, but I am trying to get in better physical condition, so I can handle four sets on my feet and not be crippled from moving my Mesa amps and the PA.
Good luck!
Bill